Test and analysis on the seismic performance of a steel truss-to-circular CFT column sub-assembly

• Connections between steel truss and CFT column were tested under cyclic loading.
• Failure modes depended on relative strength between steel truss and CFT column.
• The specimen damaged on the CFT column had more ductile performance.
• Better seismic performance was obtained if CFT column was weaker than steel truss.

This paper presents an experimental and theoretical investigation on connection between steel truss and circular concrete-filled tubular (CFT) columns used for modern low-rise railway station platforms. Two full-scale cyclic tests were performed on connection sub-assembly and results showed that relative strength between the steel truss and column zone had a major effect on the subassembly's seismic performance and failure patterns. Results also indicated that a better deformability and energy dissipation capacity can be obtained if the column zone is slightly weaker than the steel truss. In addition, a simplified theoretical model was proposed to predict the experimental load–deformation histories and failure patterns. Satisfactory comparisons were observed.